add simplest I2C on G070 (next will be through DMA)

G0:G070/i2c/i2c.h

@@ -0,0 +1,43 @@
+/*
+ * This file is part of the i2cscan project.
+ * Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#define I2C_ADDREND  (0x80)
+
+typedef enum{
+    VERYLOW_SPEED,
+    LOW_SPEED,
+    HIGH_SPEED,
+    CURRENT_SPEED
+} I2C_SPEED;
+
+extern I2C_SPEED curI2Cspeed;
+extern volatile uint8_t I2C_scan_mode;
+
+// timeout of I2C bus in ms
+#define I2C_TIMEOUT             (100)
+
+void i2c_setup(I2C_SPEED speed);
+uint8_t read_i2c(uint8_t addr, uint8_t *data, uint8_t nbytes);
+uint8_t read_i2c_reg(uint8_t addr, uint8_t reg, uint8_t *data, uint8_t nbytes);
+uint8_t read_i2c_reg16(uint8_t addr, uint16_t reg16, uint8_t *data, uint8_t nbytes);
+uint8_t write_i2c(uint8_t addr, uint8_t *data, uint8_t nbytes);
+
+void i2c_init_scan_mode();
+int i2c_scan_next_addr(uint8_t *addr);